Manufacture of hydrogen by the partial liquefaction of gaseous mixtures containing the same



Aug. 2', 1932. G CLA UDE MANUFACTURE OF HYDROGEN BY THE PARTIALLLZQUEFACTION 0F GASEOUS MIXTURES CONTAINING THE SAME Filed May 4, 1.925

AZ orwey Patented Aug. 2, 1932 UNITED STATES PATENT OFFICE onononsCLAUDE, or PARIS, FRANCE, AssIGNon T soonirn' LAIR LIQUIDE, socntrnANomE roun LETUDE ET LEXPLOITATION n-ns PRoc'EDns GEORGES CLAUDE,

SIEGE SOCIAL, OF PARIS, FRANCE MANUFACTURE OE HYDROGEN BY THE PARTIALLIQUEEACTION 0F GASEOUS MIXTURES CONTAINING THE SAME Application filedMay 4, 1925, Serial No. 28,028, and in France May 15, 1924.

This invention relates to the manufacture of hydrogen by the partialliquefaction of gaseous mixtures containing the same, such as coke ovengases, ordinary illuminating gas or the like.

It has been observed that owing to the nitrogen generally contained inthe gases treated being the most diificultly liquefiable of theconstituents other than hydrogen, the m liquid nitrogen which is lastproduced (namely in the coldest part of the column wherea very lowtemperature is obtained by the use ofcold expanded hydrogen) subj ectsthe residual compressed gases to a washing which efiectively completesthe elimination of the carbon monoxide.

It has also been observed that by adding to the compressed hydrogen(which constitutes the residual gas from the liquefaction process) priorto its expansion with the external work, a certain proportion of coldcompressed nitrogen, this nitrogen liquefies at the end of eachexpansion and serves to ensure the lubrication-of the expansion engine.

The object of the present invention is to improve the washing of theresidual compressed gases with liquid nitrogen, especially in the casewhen the gases treated contain I but little nitrogen, by utilizingtherefor the 0 nitrogen required for the lubrication of the expansionengine.

According to the present invention in processes for the manufacture ofhydrogen by partial liquefaction of mixtures of gases 5 containing thesame, such as coke oven gas or ordinary illuminating gas, a method forimproving the purity of the as obtained consists in employing for thenal washingof the compressed hydrogen, prior to its expan-' 40 sion, thenitrogen intended for the lubrica tion of the expansion engine whereinthe hydrogen is expanded, said nitrogen being pre-- viously liquefied.Preferably the said nitrogen is liquefied and cooled to a temperatureofabout 200 C. or lower.

In order that the said invention may be clearly understood and readilycarried into effect, there will now be described one method by way ofexample of carrying out the process in accordance with the presentinvention.

The' current of nitrogen required for the lubrication, after an initialcooling in the temperature exchangers, is subjected first if requ. redtoan additional cooling in a system charged into a rectifying columnprovided with Raschig rings or with plates, said column constituting aprolongation of the nest of tubes that supply the compressed residualhydrogen which still contains small quantit es of carbon monoxide. ofthe very cold liquid nitrogen, a suiiicient quantity of which must ofcourse be used, all the carbon monoxide is retained. The nitrogen, byefi'ecting this liquefaction of the carbon monoxide in the course of itspassage through the rectifying column, itself becomes heated and thenvaporized. Preferably a suflicient quantity of this washing liquid isemployed to allow of an excess of liquid nitrogen rema ning with thecarbon monoxide condensed by the saidliquid nitrogen; in this case thisexcess is discharged into the collector at the bottom of the nest oftubes in which the liquefaction of the greater part of the carbonmonoxide takes place. The re mainder of the n trogen, which is vaporizedas mentioned above, becomes mixed with the hydrogen and liquefies in theexpansion englue, the liquid thus produced acting as a lubricant undernormal conditions.

The annexed drawing shows diagrammati- Under the action 7 cally, by wayof example, one form-0f apparatus suitable for carrying out the presentprocess.

The gaseous mixture, for instance coke oven gas, arrives in compressedand purified condition at A at the heat-exchanger-B in which it iscooled by the separated gases coming out from the apparatus. -It passesthrough pipe C at the bottom of the heatexchanger to the bottom of theliquefaction apparatus proper and ascends the tube bundles F, F whileliquefying. The two liquids that. collect, one consisting chiefly ofmethane and the other of carbon monoxide, are raised by pipes D and Eand discharged at theex-; terior of bundles F and F to be vaporized.After passlng through tubes F, the compressed gaseous mixture consistingchiefly of hydrogen with small quantities of carbon monoxide andnitrogen enters a rectifyin column G filled with Raschig rings in whicit is washed by liquid nitrogen introduced at the top of the column atH. The purified and very cold hydrogen, which still contains a certainamount of nitrogen, escapes at I and is expanded in the expansion engineK, the lubrication of which is provided for by the nitrogen contained inthe expanding gas. The expanded hydrogen from the engine circulatesfirst around the tube bundle L containing the liquid nitrogen that isintroduced into the column at H; it then passes around the upper part ofthe bundle F and then is delivered to the lower ends of the centraltubes of the bundle of exchangerB and escapes at the top of the tubes atX. The gas rich in carbon monox de which is vaporized around tubes Fpasses around the tube bundle M wherein circulates the liquid nitrogenwhich goes afterwards to bundle L; then this carbon monoxide is joinedto the gas rich in methane which is vaporized around tubes F, passesthrough a part of heat-exchanger B and finally escapes at Y. Thecompressed gaseous nitrogen arrives at N at the heatexehanger B in whichit is cooled and liquefied by the separated gases circulatingtherethrough; the liquid nitrogen formed passing through a regulatingvalve 0 which brings it to the pressure necessary for its introduc tionat H into the washing tower or column G after circulation through thetube bundles M and L in which it is su temperatures.

mitted to very low When there is used in column G an ex-' fcessiv equantity of liquid nitrogen, the excess nitrogen descends with thecarbon monoxide of column G through the interior of tubes F and iscollected at P with the carbon monoxide and, eventually, the nitrogenwhich are condensed in tubes F; then the liquid from collector P isdischarged through pipe E around the tube bundle F.

Of course, the gas rich in carbon monoxide vaporized around tubes F, andthe gas rich in methane vaporized around tubes F, may not be broughttogether, butmay be circulated separately through the exchanger B.

I claim as my invention:

1. A process for separating the constituents of gaseous mixtures, bypartial liquefaction, which comprises expanding with production ofexternal work the residual gaseous product of said liquefaction, usingthis cold expanded product for liquefying a washing medium, using thisliquefied medium for washing the residual gaseous product while stillunder pressure and using the gaseous medium as lubricant in the aboveexpansion.

2. A process for separating the constituents of gaseous mixtures, bypartial liquefaction, .which comprises purifying the residual gaseousroduct of sad liquefaction under pressure y a washing liquid medium,expanding the gaseous product and circulating it in indirect contactwith the gaseous mixture under liquefaction immediately before the saidpurifying step.

3. A process for separating the constituents of gaseous mixtures, bypartial liquefaction, which comprises purifying the residual gaseousproduct of said liquefaction under pressure by a washing liquid medium,expanding the gaseous product, and circulating it in indirect contactfirst with the washing medium and then with the gaseous mixture underliquefaction immediately before the said purifying step.

4. A process for separating the constituents of gaseous mixtures, bypartial liquefaction, which comprises purifyifig the residual gaseousproduct of said liquefaction un der pressure by a washing liquid medium,thereafter expanding the gaseous product with production of externalwork, and using the gaseous medium as lubricant in the above expansion.f

5. A process for obtaining a hydrogen-nitrogen mixture in the separationby partial liquefaction of the constituents of gaseous m xturecontaining hydrogen, which comprises liquefying compressed gaseousnitrogen by the cold expanded hydrogen-nitrogen mixture obtained as theresult of the operation, using this liquid nitrogen for washing thecompressed residual gaseous product of the separation by liquefaction,expanding. with production of external work the hyd ro gen-nitrogenmixture obtained, and using this cold expanded mixture for the aboveliquefaction of the nitrogen and for the partial liquefaction of thegaseous mixture.

6. A process of manufacturing hydrogen.

comprising the steps of partially liquefying a gaseoushydrogen-containing mixture. thereby obtaining compressed residualhydrogen; liquefying a current of nitrogen; washing the compressedresidual hydrogen with the liquid nitrogen; expanding the washedhydrogen; and circulating said washed bydrogen in indirect contact withthe gaseous mixture under liquefaction immediately before the saidwashing step.

7. A process of manufacturing hydrogen in apparatus includingheat-exchanging means and an expansion engine,comprising the steps ofpartially liquefying a gaseous hydrogen-containing mixture, therebyobtaining compressed residual hydrogen; subjecting a current of'nitrogento an initial cooling in heat-exchange relation with the separatedproducts and then to an intense final cooling-in heat-exchange relationwith expanded hydrogen, whereby the nitrogen is liquefied; washing thecompressed residual hydrogen with the coldliquid nitrogen; and

then expanding the washed hydrogen with production of external work.

8. A process for separating gaseous'mixqtures' by partial liquefaction,which comprises cooling to liquefaction the compressed gaseous mixtureand a gaseous medium, further cooling the thus liquefied medium by meansof separated products, washing under 2 pressure by said cold liquidmedium the compressed residual gas of the partial liquefaction, andusing the liquid re sulting from said washing in the liquefaction of thegaseous mixture.

9. A process for separating the constituents of gaseous mixtures byliquefying a partof said constituents and expanding the whole amount ofnon-liquefied constituents, which comprises the steps of totallyliquefying a single gas and further cooling the same 'by means of thecold expanded non-liquefied constituents; and washing the saidnon-liquefied constituents of the gaseous mixture, while still underpressure, with said liquefied and cooled single gas.

10. A process for separating the constituents of gaseous mixtures byliquefying a part of said constituents and expanding the whole amount ofnon-liquefied constituents, ,which comprises the steps of totallyliquefying a single gas and further cooling the same by means of thecold ex panded non-liquefied constituents and the cold separatedproducts of the liquefaction; and washing the said non-liquefiedconstituents of the gaseous mixture, while still under pressure, withsaid liquefied and cooled single gas.

11. A process for separating gaseous mix- 7 tures by partialliquefaction, which comprises cooling to liquefaction the compressedgaseous mixture and a gaseous medium \in heat exchange with all theseparated products resulting from the separation, further cooling thethus liquefiedmedium by means of cold separated products, and washingunder pressure by said cold liquid medium the com pressed residual gasof the partial liquefaction.-

12. A process-of manufacturing hydrogen,

i washed hydrogen in indirect contact with the gaseous mixture underliquefaction immediately before the said washin step.

In testimony whereof I a x my signature.

GEORGES CLAUDE.

